1. Field of the Invention
This invention pertains to dispensing of a fluid from a dental instrument. More particularly, a cleaning agent such as prophylactic paste is dispensed from a manually controlled dispenser coupled to conventional hand-held tooth cleaning implements, enabling one-handed application of a tooth cleaning agent to the patient's teeth from the dental instrument without having to remove the instrument from the patient's mouth.
The tooth cleaning agent or other fluid is dispensed from a storage container that is integrated with a prophy angle headpiece. The headpiece is coupled to the dental instrument handpiece which supplies the mechanical force required to rotate the prophy cup.
2. Prior Art
Application of a fluid cleaning agent such as a prophylactic paste to a patient's teeth by an oral hygienist or a dentist is a common part of professional teeth cleaning. Typically, a prophy cup mounted on the end of a headpiece coupled to a dental instrument handpiece is dipped into a prophylactic paste-filled container to fill the cup. A portion of the headpiece and possibly a portion of the instrument handpiece is placed in the patient's mouth while the prophy paste-filled cup is pressed against the patient's teeth. The prophy cup is rotated by a system of gears in the headpiece that is coupled to a pneumatic actuation mechanism in the instrument handpiece. The paste is used rapidly, thus the prophy cup must be withdrawn from the patient's mouth and returned to the paste container often for refilling. The cleaning process is unnecessarily complicated and prolonged by the repeated refilling of the prophy cup.
Efforts have been made in the prior art to develop an apparatus capable of shortening the cleaning process. Typically, such efforts have concentrated on elaborate teeth cleaning prophy angle headpieces, new instrument handpieces, or a combination of the two. These devices generally include some type of paste container integrated with the dental instrument itself, and an apparatus for delivering paste from a container to the prophy cup. The prior art is typically represented by U.S. Pat. Nos. 2,400,912, 2,738,528, 3,775,849, 3,987,550, 4,220,446 and 5,062,796.
The aforementioned patents exemplify most of the elements of the prior art which partially explains the lack of success of any of these prophylactic paste dispensing prophy angle devices. For example, U.S. Pat. No. 2,738,528 might appear similar to the present invention because it shows a flexible paste-filled container strapped to the top of a headpiece. However, while the design is appealing because of its simplicity, close examination of the implementation readily accounts for its flawed performance which make it impractical for actual use. The design shows a flexible tube bent so as to allow paste in a collapsible dispenser to be manually propelled through a flexible tube by passing through the prophy cup headpiece and into the prophy cup. The tube is prone to kinking because the angle down into the headpiece is made of flexible material, interrupting paste flow and delaying cleaning. Using the container tubing as the path down through the headpiece for the cleaning agent also results in a loss of volume, thereby decreasing usable inside diameter of the lumen which can lead to increased flow resistance. The container tubing will also cause friction between the tube and the rotating shafts, especially if the tubing is an elastomeric material. Also, the shape of the paste container is round, having no surface for stabilizing the container when pressed, making it unwieldy and difficult to handle as it would twist from side-to-side. In addition, the anchoring system is a single strap that can be dislodged when the container is emptying, making the device even more awkward to use. Finally, the container as embodied would have to be filled from the narrow lumen end, thus leading to increased difficulty and cost of the system.
U.S. Pat. No. 4,220,446 is a good illustration of how prior art designs are often bulky and ill-suited for being inserted in or near the patient's mouth without interfering with an operator's view or instrument access to the mouth. It also requires a secondary pneumatic source for dispensing of the paste, further complicating the design. Finally, the instrument only dispenses paste to the side of the cup, not in it as desired.
Far more common in the prior art are major modifications to the dental instrument handpiece itself. U.S. Pat. Nos. 5,062,796, 3,987,550, 3,775,849 and 2,400,912 illustrate such redesigns of the instrument handpiece. The handpiece typically incorporates a pneumatic pressure system for driving paste from a container and into a prophy cup. The major drawback to such designs is the retooling that dental instruments already installed would require, as well as the cost of an elaborate device that would now be prone to break because of the additional moving parts. Some of these designs even include foot-pedals or other elaborate actuation and control means that unnecessarily complicate the instrument design. By constructing the dispensing container inside the handpiece, the device is no longer disposable. The entire device must be cleaned and sterilized before each use. Furthermore, it is more difficult to change cleaning agents during the procedure if required. The fact that these designs are not in use today demonstrates their impracticality.
If implemented correctly, integrating a paste supply with the instrument handpiece overcomes the problem of having an instrument small enough not to interfere with the cleaning process. However, the addition of a mechanism for delivering the paste from the container to the prophy cup complicates the design and increases costs to such a degree, as demonstrated by the lack of any such device that the inventors are aware of on the market, to make the concept impractical.
Accordingly, the challenge in designing a dispensing system for fluid substances such as the prophy paste that would be an improvement over the prior art is to provide a device that uses existing dental instrument handpieces without having to redesign them for fluid storage or dispensing. It would also be an improvement to provide a device that is simple to use, doesn't interfere with visual or instrument access to a patient's mouth, provides easily replaceable fluid containers, and offers a variety of different fluid dispensers for a user to choose from while providing a disposable headpiece that at a low cost.